A 10 000 W fiber laser was used to carry out the process experiment of magnetic field assisted laser swing welding of 10 mm thick 6061-T6 aluminum alloy. Ultra-depth-of-field microscopy and scanning electron microscopy (SEM) were used to analyze the macro-morphology and micro-structure of the weld section. Under the action of magnetic field assisted laser swing welding, the defects such as sagging, spattering and pitting of welded joints are obviously restrained. Then , the behavior characteristics of the molten pool and the small holes during the welding process were directly observed by high-speed camera, and it was observed that the magnetic field has the effect of stabilizing the flow of the magnetic field. Then X-ray flaw detection was carried out to test the porosity of the weld. The porosity of the 200mT magnetic field-assisted laser swung welding was the smallest, which could reach 0.856%. Finally, the tensile property test was carried out , and the tensile strength of magnetic field-assisted laser swing welding can reach 318.85 MPa at the highest.